from my understanding, you should NEVER put a kitten on a diet (unless your vet feels for some reason that it's necessary), and as some mention here, i free feed my kittens throughout the day and for them, it works, but being the age your cat is, you really should be feeding him more than twice a day. you mentioned that you got your cat from a breeder, what breed is he? i have Ragdolls, and until they are a year old, i can not follow feeding suggestions on kitten food? why? because no where do they tell you what you "should" feed a 6 month old 9 pound kitten (my kitten will be the same size as yours next month...remember that some breeds are just large and they get very large very fast, and they'll need to eat more.) . so i free feed and my kittens eat only as much as they need to. when they first started to have their growth spurt, i was feeding them a purina (i believe it was Purina One) food, they went through 2.5-3 pounds of food in 5
i was terrified that they can eat that much, but they were fine and didn't balloon out. i changed them to a higher quality food (Nutro Complete), and they now only eat about a third of what they did and they're still growing like weeds. maybe you should think of switching to a different food.
also at times, i'm afraid that my kittens are getting chunky (Ragdolls are almost all fur though LOL AND like lions, they get a good sized fatty pouch on their tummies, but that's perfectly normal and healthy for them), but the only real way you can tell on a cat if they are overweight is not by looking at the scale or just glancing at them, you need to do some different things. 1) can you feel the upper ribs and the spine? it shouldn't feel boney, but you should be able to feel they are there without having to prod through a lot of fat. 2) look at your cat from up above, depending on the breed, you may want to wet him down first if he has a lot of hair. from up above, does he look like he has a slight indentation for a waist? if he does, then he's a fine weight, if he bulges in the middle, then he is overweight.
you may want to feed your kitten 3-4 small meals a day--which from reading your posts you feel is a pain--and give him just a little more food to work with. and please remember, he's not doing this to be spiteful or to make you angry. just have a little patience and find something that works for the both of you.
(and i happen to disagree with disciplining him for being hungry. if you have to, put him in another room for the night so that you can sleep...do you give wet food at all? giving a tablespoon or so of wet food before bed or having a nice long play should tire him out so that he won't continue to wake you.)